What exactly is the difference between a surge protector and a fuse? Can a fuse protect the electronic devices from lightning instead of surge protector?
11.06.2025 00:10
These are simplified answers to the original question, and does not change anything I wrote above.
The other is “what does a “fuse” do?”
There are three different concepts here that are getting confused.
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“ … to protect building, lightning arrestor, is provided above building and directly connected to earth.”
One
This is where this question deviates from being a 'generic' question, and becomes more specific.
An AC voltage/ current source, and an ac inductive load.
If the nominal power is 4,000 watts then the current at 230volts is 16 amps.
This one hit behind the barn.
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The third is lightning and “how it gets conducted into a home.”
Is the question then , "why buy a surge supressor, if the fuse alone protects the electronic circuits from a lightning bolt?".
In schematic diagrams this is the symbol for a fuse:
There are two important concepts here.
For this case there are devices called Metal oxide varistors (MOV).
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What did your mother say that made your jaw drop?
The MOV will conduct when the voltage exceeds 50% of line voltage.
The bolt then partially travels down the line to your home.
So, it’s possible that these devices from Trip Lite have addition suppression devices, these ones seem to be sturdy.
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This device then solves the entire problem.
At least they know the answer if they wanted it.
A fuse is a non-resetable over current circuit protector.
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2024–10–00 [ Ammar Mahdi ] Ammar Mahdi
Fuses, on their own, then operate much slower than the MOV variable resistance, during the lightning strike.
And this is the problem alone. Is the power supply in the equipmemt designed with a lightning strike in mind? Some yes, others, no.
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When the current is 200% of the rated value , it will “go open” (the link metal melts) and protect the device.
2024–09–27 [ Mohan Rajaratnam Mohan Rajaratnam ] . Thinks you can get free electricity from nothing : Mohan Rajaratnam's answer to Is it possible to generate free electricity at home using a magnet or other low-cost methods? If so, how does it work?
What is lightning?
Once the voltage goes over 0.0650 volts, then this fact can be used to amplify the difference, and turn the circuit breaker off , furthur down the line. Essentially that is what a RCD/GFCI does, it compares the incoming current, to the outgoing current, and if the difference between the two currents is over 5mA, then it trips the circuit breaker.
He then asserts :
But during the surge, the fuse will not blow if it is a longer duration and lower value )10 to 50%).
Here is a simplified AC power diagram.
Barnstars:
But it can get overloaded, and no longer works.
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(Dc diagram shown, AC is similar).
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so, what happens?
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2024–10–10[John johnson John Johnson ]
2024–10–11 [Bobby Sanchez Bobby Sanchez ].
What does a fuse do?
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“ A surge suppressor is the one which is connected at the input supply so that when there is a sudden change voltage it bypasses thereby protecting the (circuit) and electronic components”
but I think this circuit , shows a few more pieces.
(There is no concept of polarity, in the loop because the current changes direction 100 to 120 times a second (power frequency).
I post the exact comment here.
2024–10–11 [Victor Olarewsju Victor Olarewaju ]
This is where the MOV conducts again, and dissipated the energy.
2024–10–16 [ OO OLAOYE OYEBODE ]
One is “what exactly is in a ‘surge protector’ ? ”
Upvotes:
the problem then depends on "how fast does the fuse operate?".
It also is a device that limits the change in current flow.
So, the voltage could go up to 500 volts, and the fuse will not open up.
what exactly is a ‘surge’ protector?
This is the picture of an electronic coil of wire wound around a core of magnetic material.
“ A fuse is a device which protects the (circuit) against overload and short circuit.”
At the secondary, it is 1000 times less.)turns ratio). If it gets hit with a 100,000 volt bolt of lightning then the voltage arrestors conduct and clamp the voltage down to line voltage, ( but a small amount leaks down the line). This is the problem.
so, the loop of wire then, when put together with another loop reduces the ‘noise’ on a power line.
This is an electronic circuit designed to clamp voltages so that the Voltage Potential that appears at the outlet is never going to exceed the nominal value.
[image of Common-mode choke]
Would individual surge supressors have save this equipment? most likely, since the surge supressor would take the jolt instead of the electronic components.
He then describes the function of a fuse.
At one ohm, the resistor has a maximum of 1 watt power.
Now when you have a certain ac resistance, then a current flows in a loop.
There is no harm in having the surge suppressor along with the fuse in the circuit. The fuse will not open up until the current melts the link. This will take time, and in the interim, that jolt will get transmitted into the power supplies.
This is a high voltage low current spike that comes down the line because of the power poles being struck, and the voltage suppressors activating on the primary side of the transformer.
It seems Mohan does not understand the difference between a comment and an Answer.
Edit 2024–10.
Can the fuse protect the electronic devices from lightning instead of a surge protector.
Lightning arrestor is a spark-gap device, and can be installed anywhere. What is important, is that the wire is thick enough to withstand the lightning bolt and conduct the energy away from the building.
But… the neutral is now “floating” because of the 1 ohm resistance.
a photo is worth a thousand words.
Because the load is inductive, the current lags the voltage.(by a bit).
2024–10–14 [Omar Gharbi Omar Gharbi ]
[old diagram got deleted by accident]
OK, this is Mohan Rajaratnam’s definition of a Surge suppressor.
P = e* I, so since I is 16 amps, then the voltage dropped is 1/16 volt or 0.0650 volts.
but this device (an Inductor) … impedes the rapid changes in the current.
This is 'the assistant's answer'
So combined with a device called a MOV or Metal-oxide-resistor, then forms the 3rd part of a “surge suppressor “.
It’s been three xxx five werks, and there has been no response to my follow on query on his Commment to my answer.
Mohan forgets that a fuse is a one-time device, and needs to be replaced if it is tripped.
This is a photo where a lightning bolt took out a home's complete mains distribution box, and a lot of electronic gear as well.
A circuit breaker is similar, but is resettable.
These devices are installed between the “hot” and “neutral” and protective ground.
He then describes Rainy Season and Lightning.
First Sentence: